natural causes

Noun

of death or dying plural plural-only usually

(usually of death or dying) Causes such as illness or disease.

Japanese Meaning

自然死：病気や体調不良など、非外傷性かつ自然な原因によって生じる死

The coroner concluded that he had died of natural causes after a thorough examination.

検視官は念入りな調査の末、彼は病気などが原因で死亡したと結論づけた。

Sense（1）

(usually of death or dying) Causes such as illness or disease.

Some military casualties are by natural causes and accidents.